Induction-coil.



A. L. PARCELLE. INDUCTION GOIL.

APFLIUATION FILED AUG. 15. 1901.

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PATBNTED MAR. 17, 1903.

nUNTTED STATES l PATENT OFFICE.'

ALBERT L. PAROELLE, OF BOSTON, MASSACHUSETTS.

INDUCTION-colt;

sr'nc'rnonfrron forming part of Letters Patent No. 723,016, dated March 1v, 1903.

Application led August-15, 1901. Serial No. 72,152. (No model.)

Y simplest form, I have shown it as embodied in a telephone; but itwill be understood at the outset that its application is not limited thereto, but may be extended to various other fields of electrical work.

thereto, whereby the passage of a current of` electricity through either of said primary coils will affect the electrical condition of the secondary coil.

As shown upon the drawings, the invention is embodied in a telephone having a receivercircuit including a secondary coiland two independent transmitter-circuits each having its primary-coils in inductive relation to the said secondary coil. The transmitter-circuits act to induce an alternating current in the receiver-circuit, the initial direction of the alternations in the current caused by said transmitter-circuits being opposite. This is achieved by employing transmitter-circuits whose currents are of opposite polarity, or in the case of circuits having currents of the same polarity by winding the coils of the primaries in said circuits in different directions. By this construction and arrangement, together with the fact that the transmitters are so arranged that the variable-resistance medium of one is compressed when the other is eX- panded, an increase in conductivity in one transmitter-circuit is synchronous with the decrease in conductivity of the other transmitter-circuit. It follows, therefore, that the current induced in the secondary coil by the collapse or waning of the current in one transmitter-circuit is strengthened by the simultaneous induction of current in the same direction in said secondary coil by a current or bers of the two transmitters, whereby the compression of the variable-resistance medium in one transmitter will be synchronous with the expansion of said mediumin the other transmitter. The effect of this is a much more faithful reproduction of pitch, loudness, and timbre or quality of vocal sounds than has hitherto been possible.

Referring to the accompanying drawings, Figure l represents a telephone embodying the invention. Fig. 2 represents a section on the line 2 2-of Fig. l.

On the drawings, d b indicate two primary circuits, each shown as including a battery d b', respectively, although'a single battery may be used if properly connected. The secondary circuit (indicated at c) includes the telephone-receiver c and the secondary coil c2, made of fine wire in the usual way. The primary coils d3 b5 are wound upon independent cores d* b4, respectively. Each core consists, preferably, of line soft-iron wires and they diverge, as shown in Fig. l, whereby each core is substantially U-shaped to prevent material magnetic leakage. By virtue of the ends of the cores being Widely separated quick action in discharging is promoted, especially when a direct current is employed for exciting them; but it will be apparent that where the current in the primaries is alternating then the ends of the cores may be brought together to form a closed magnetic circuit. A double transmitter or two oppositely-acting microphones are employed, as indicated somewhat conventionally. Two stationary members a5 b5, properly insulated from each other, are used in conjunction with two movable members a of, rigidly connected together, as by the pin or screw d. The said members may be made of ICO carbon or other conducting material. Between each stationary member and its coacting movable member is placed a variable-resistance medium al or bl, as the case may be, such as granular carbon. The vibratory diaphragm e is connected rigidly to the member a or the pin or screw d.

Operation: Assuming that the diaphragm be moving inward, the variable-resistance medium a7 will be compressedand that at h7 expanded. The conductivity in circuit d will be increased and a current tiow from battery a' through primary coil d3 around core d4. This induces a current in the secondary circuit c in the opposite direction by reason of the magnetic lines set up in core a4. Asthe diaphragm springs back by its inherent resiliency the current in circuit a is weakened and the collapse of the magnetic lines of force in core 0,4 induces a change of current in the secondary c2 oppositelyY-Vto the initial direction. Synchronously with the collapse of said magnetic-lines the granules hl are compressed,whereby a current flows from battery b' through primary coil h3 in a direction opposite to the direction of the first-mentioned current through primary d3, Thereupon a current is induced in secondary coil c of the same direction and phase as that induced by the collapse of magnetic lines in core CL4, so that the full strength and benefit of both batteries are obtained at the time most desirable. This operation is repeated for each vibration of the diaphragm. The two sources of electricity do not injure the microphones or double transmitter, their effect and iniiuence being on the secondary only of the induction-coil. As they are both controlled by a single diaphragm they are always in proper phase relation to each other, so that at the impingement of each sound-wave upon the diaphragm the batteries are thrown upon the line in succession, so as not to interfere with or counteract each other.

It is a matter of common knowledge that it has been proposed to use an alternating current in conjunction with a single primary winding and also to employ two primaryrcoils on.a single core; but these contrivances do not accomplish the results achieved by my invention and are foreign thereto, as will be appreciated by those skilled in the art.

I do not herein claim the method of transmitting sounds which has been described in detail, nor do I herein claim the telephone system which includes independent transmitter-circuits each including a primary coil and the core therefor in operative relation to a single secondary coil, a variable-resistance medium for each transmitter-circuit adapted to be controlled by a diaphragm, and a receiver in the secondary circuit.

Having thus explained the nature of the invention and a simple way of constructing and using the same, without, however, attempting to set forth all of its embodiments or all the forms in which it may be made, what I claim ise l. In combination, a plurality of independent cores, and a common secondary coil in inductive relation thereto.

2. In combination, a 'secondary coil, a plurality of independent primary coils in operative relation thereto, and an independent core for each primary coil'.

3. In combination, a plurality of independent cores, primary coils on said cores, a common secondary coil, and means for effecting successive variations'in current in said primary coils.

t. In combination, a secondary coil, two independent primary circuits having their coils in operative relation to said secondary coil, an independent core for each primary coil and means whereby said primaryrcircuits induce currents in said secondary coil with the electrical impulse of one primary circuit synchronous with the wane or decline of the current in the other primary circuit, so that one inductive impulse is superimposed upon another in the secondary circuit.

5. In combination, a secondary coil, a plurality of diverging cores in said coil, and a plurality of independent circuits including primary coils on said cores.

6. An induction-coil comprising independent primary coils, a common secondary coil in inductive relation thereto, and independent cores for said primary coils constructed and arranged to prevent material magnetic leakageV from one to the other.

7. A transformer with multiple cores, each core having a primary winding and acting independently of the other cores.

8. In a transformer, a secondary coil in inductive relation to two or more primary coils, each having its own core, andeach acting independently on said secondary coil.

In testimony whereof I haveafxed my signature in presence of two witnesses.

ALBERT L. IARCELLE.

Witnesses:

M. B. MAY, U. F. BROWN.

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